Naomi Sadeh

Serotonin transporter gene associations with psychopathic traits in youth vary as a function of socioeconomic resources.

Although prior research has examined the genetic correlates of antisocial behavior, molecular genetics influences on psychopathic traits remain largely unknown. Consequently, we investigated the influence of polymorphic variation at the serotonin transporter protein gene (SLC6A4) and socioeconomic resources (SES) on psychopathic traits in youth across two distinct samples in two separate studies. In Study 1, a main effect of serotonin transporter (5-HTTLPR) genotype was associated with the impulsivity dimension of psychopathy. That is, individuals homozygous for the short allele evidenced more impulsivity than did those homozygous for the long allele. In contrast, a gene-environment interaction was associated with the callous-unemotional and narcissistic features of psychopathy. Callous-unemotional and narcissistic traits increased as SES decreased only among youths with the homozygous-long (l/l) genotype, a novel finding replicated and extended in Study 2. These studies provide preliminary results that the l/l genotype confers risk for the emotional deficits and predatory interpersonal traits associated with psychopathy among youths raised in disadvantaged environments.

Traumatic stress, oxidative stress and post-traumatic stress disorder: neurodegeneration and the accelerated-aging hypothesis

Post-traumatic stress disorder (PTSD) is associated with elevated risk for a variety of age-related diseases and neurodegeneration. In this paper, we review evidence relevant to the hypothesis that chronic PTSD constitutes a form of persistent life stress that potentiates oxidative stress (OXS) and accelerates cellular aging. We provide an overview of empirical studies that have examined the effects of psychological stress on OXS, discuss the stress-perpetuating characteristics of PTSD, and then identify mechanisms by which PTSD might promote OXS and accelerated aging. We review studies on OXS-related genes and the role that they may have in moderating the effects of PTSD on neural integrity and conclude with a discussion of directions for future research on antioxidant treatments and biomarkers of accelerated aging in PTSD.

Psychopathic Personality Traits Associated with Abnormal Selective Attention and Impaired Cognitive Control

The current study investigated how mechanisms of attention that have been well-characterized in the cognitive psychology literature (Lavie, Hirst, De Fockert, & Viding, 2004; Maylor & Lavie, 1998) may be differentially associated with psychopathic traits in nonincarcerated men. Previous research on cognition and psychopathy indicated that primary psychopathic traits were associated with overfocused attention and/or reduced processing of information peripheral to the focus of attention. Conversely, deficits in executive functioning, such as working memory and cognitive control, were implicated in secondary psychopathic traits. Results revealed a significant relationship between traits typically associated with primary psychopathy (e.g., low anxiety, social dominance, fearlessness, callousness) and reduced processing of task-irrelevant distractors, suggesting diminished basic attentional capacity among individuals high on these traits. In contrast, some characteristics linked to secondary psychopathy (e.g., social alienation, cynicism) showed a positive relationship with impaired working memory functioning, indicative of deficits in cognitive control, whereas other traits (i.e., self-centeredness, antagonism) did not. These results suggest that psychopathic traits are differentially related to selective impairments in attentional functioning, which may help explain the observed heterogeneity in psychopathic manifestations.

Stress-Induced Asymmetric Frontal Brain Activity and Aggression Risk

Impersonal stressors, not only interpersonal provocation, can instigate aggression through an associative network linking negative emotions to behavioral activation (L. Berkowitz, 1990). Research has not examined the brain mechanisms that are engaged by different types of stress and serve to promote hostility and aggression. The present study examined whether stress exposure elicits more left than right frontal brain activity implicated in behavioral approach motivation and whether this lateralized brain activity predicts stress-induced aggression and hostile/aggressive tendencies. Results showed that (a) participants in the impersonal (assigned to stress by a computer) and interpersonal (assigned to stress by a provoking confederate) stress conditions both showed more left than right frontal electroencephalogram activity after condition assignment and stress exposure and (b) the 2 stress groups exhibited subsequent increases in aggression relative to the no-stress group. Importantly, left frontal asymmetry in response to stress exposure predicted increases in subsequent aggressive behavior, a finding that did not emerge in the no-stress condition. Thus, both the interpersonal and impersonal stressors impacted state changes in brain activity related to behavioral approach, suggesting that stress reactivity involving approach activation represents risk for behavioral dysregulation.

Borderline personality disorder as a female phenotypic expression of psychopathy

Evidence suggests that the combination of the interpersonal-affective (F1) and impulsive-antisocial (F2) features of psychopathy may be associated with borderline personality disorder (BPD), specifically among women (e.g., Coid, 1993; Hicks, Vaidyanathan, & Patrick, 2010). However, empirical research explicitly examining gendered relationships between BPD and psychopathy factors is lacking. To further inform this area of research, we investigated the hypothesis that the interplay between the two psychopathy factors is associated with BPD among women across two studies. Study 1 consisted of a college sample of 318 adults (51% women), and Study 2 consisted of a large sample of 488 female prisoners. The interpersonal-affective (F1) and impulsive-antisocial psychopathy (F2) scores, measured with self-report and clinician-rated indices, respectively, were entered as explanatory variables in regression analyses to investigate their unique contributions to BPD traits. Across two independent samples, results indicated that the interaction of high F1 and F2 psychopathy scores was associated with BPD in women. This association was found to be specific to women in Study 1. These results suggest that BPD and psychopathy, at least as they are measured by current instruments, overlap in women and, accordingly, may reflect gender-differentiated phenotypic expressions of similar dispositional vulnerabilities.

Accelerated DNA methylation age: Associations with PTSD and neural integrity.

BACKGROUND Accumulating evidence suggests that posttraumatic stress disorder (PTSD) may accelerate cellular aging and lead to premature morbidity and neurocognitive decline. METHODS This study evaluated associations between PTSD and DNA methylation (DNAm) age using recently developed algorithms of cellular age by Horvath (2013) and Hannum et al. (2013). These estimates reflect accelerated aging when they exceed chronological age. We also examined if accelerated cellular age manifested in degraded neural integrity, indexed via diffusion tensor imaging. RESULTS Among 281 male and female veterans of the conflicts in Iraq and Afghanistan, DNAm age was strongly related to chronological age (rs ∼.88). Lifetime PTSD severity was associated with Hannum DNAm age estimates residualized for chronological age (β=.13, p=.032). Advanced DNAm age was associated with reduced integrity in the genu of the corpus callosum (β=-.17, p=.009) and indirectly linked to poorer working memory performance via this region (indirect β=-.05, p=.029). Horvath DNAm age estimates were not associated with PTSD or neural integrity. CONCLUSIONS Results provide novel support for PTSD-related accelerated aging in DNAm and extend the evidence base of known DNAm age correlates to the domains of neural integrity and cognition.

Suicidality as a Function of Impulsivity, Callous-Unemotional Traits, and Depressive Symptoms in Youth

Suicidality represents one of the most important areas of risk for adolescents, with both internalizing (e.g., depression, anxiety) and externalizing-antisocial (e.g., substance use, conduct) disorders conferring risk for suicidal ideation and attempts (e.g., Bridge, Goldstein, & Brent, 2006). However, no study has attended to gender differences in relationships between suicidality and different facets of psychopathic tendencies in youth. Further, very little research has focused on disentangling the multiple manifestations of suicide risk in the same study, including behaviors (suicide attempts with intent to die, self-injurious behavior) and general suicide risk marked by suicidal ideation and plans. To better understand these relationships, we recruited 184 adolescents from the community and in treatment. As predicted, psychopathic traits and depressive symptoms in youth showed differential associations with components of suicidality. Specifically, impulsive traits uniquely contributed to suicide attempts and self-injurious behaviors, above the influence of depression. Indeed, once psychopathic tendencies were entered in the model, depressive symptoms only explained general suicide risk marked by ideation or plans but not behaviors. Further, callous-unemotional traits conferred protection from suicide attempts selectively in girls. These findings have important implications for developing integrative models that incorporate differential relationships between (a) depressed mood and (b) personality risk factors (i.e., impulsivity and callous-unemotional traits) for suicidality in youth.

Inhibitory control and negative emotional processing in psychopathy and antisocial personality disorder

The field of personality disorders has had a long-standing interest in understanding interactions between emotion and inhibitory control, as well as neurophysiological indices of these processes. More work in particular is needed to clarify differential deficits in offenders with antisocial personality disorder (APD) who differ on psychopathic traits, as APD and psychopathy are considered separate, albeit related, syndromes. Evidence of distinct neurobiological processing in these disorders would have implications for etiology-based personality disorder taxonomies in future psychiatric classification systems. To inform this area of research, we recorded event-related brain potentials during an emotional-linguistic Go/No-Go task to examine modulation of negative emotional processing by inhibitory control in three groups: psychopathy (n = 14), APD (n = 16), and control (n = 15). In control offenders, inhibitory control demands (No-Go vs. Go) modulated frontal-P3 amplitude to negative emotional words, indicating appropriate prioritization of inhibition over emotional processing. In contrast, the psychopathic group showed blunted processing of negative emotional words regardless of inhibitory control demands, consistent with research on emotional deficits in psychopathy. Finally, the APD group demonstrated enhanced processing of negative emotion words in both Go and No-Go trials, suggesting a failure to modulate negative emotional processing when inhibitory control is required. Implications for emotion-cognition interactions and putative etiological processes in these personality disorders are discussed.

Gender Differences in Emotional Risk for Self- and Other-Directed Violence among Externalizing Adults.

OBJECTIVE Women and men generally differ in how frequently they engage in other- and self-directed physical violence and may show distinct emotional risk factors for engagement in these high-impact behaviors. To inform this area, we investigated gender differences in the relationship of emotional tendencies (i.e., anger, hostility, and anhedonic depression) that may represent risk for other-directed violence (i.e., physical fighting, attacking others unprovoked) and self-directed violence (i.e., self-injury, suicide attempts). METHOD The ethnically diverse sample consisted of 372 adults (252 men and 120 women age 18-55) with a history of criminal convictions. Facets of emotional risk assessed with the Aggression Questionnaire (Buss & Warren, 2000) and Mood and Anxiety Symptom Questionnaire (Watson et al., 1995) were entered simultaneously as explanatory variables in regression analyses to investigate their unique contributions to other- and self-directed physical violence in men and women. RESULTS Analyses revealed that anhedonic depressive tendencies negatively predicted other-directed violence and positively predicted self-directed violence in men and women, consistent with a model of depression in which aggression is turned inward (Henriksson et al., 1993). Gender differences, however, emerged for the differential contributions of anger and hostility to other- and self-directed violence. Trait anger (i.e., difficulty controlling ones temper) was associated with other-directed violence selectively in men, whereas trait hostility (i.e., suspiciousness and alienation) was associated with self- and other-directed violence among women. CONCLUSIONS The divergent findings for trait anger and hostility underscore the need to examine gender-specific risk factors for physical violence to avoid excluding potentially useful clinical features of these mental health outcomes.

Parallel Syndromes: Two Dimensions of Narcissism and the Facets of Psychopathic Personality in Criminally Involved Individuals

Little research has examined different dimensions of narcissism that may parallel psychopathy facets in criminally involved individuals. In this study, we examined the pattern of relationships between grandiose and vulnerable narcissism, assessed using the Narcissistic Personality Inventory-16 and the Hypersensitive Narcissism Scale, respectively, and the four facets of psychopathy (interpersonal, affective, lifestyle, and antisocial) assessed via the Psychopathy Checklist: Screening Version. As predicted, grandiose and vulnerable narcissism showed differential relationships to psychopathy facets, with grandiose narcissism relating positively to the interpersonal facet of psychopathy and vulnerable narcissism relating positively to the lifestyle facet of psychopathy. Paralleling existing psychopathy research, vulnerable narcissism showed stronger associations than grandiose narcissism to (a) other forms of psychopathology, including internalizing and substance use disorders, and (b) self- and other-directed aggression, measured with the Life History of Aggression and the Forms of Aggression Questionnaire. Grandiose narcissism was nonetheless associated with social dysfunction marked by a manipulative and deceitful interpersonal style and unprovoked aggression. Potentially important implications for uncovering etiological pathways and developing treatment interventions for these disorders in externalizing adults are discussed.